Adaptive wear leveling via monitoring the properties of memory reference stream

Abstract

Adaptive write leveling in a memory system that includes a memory that has one or more limited lifetime memory devices and an adaptive write leveling module connected to the memory. The adaptive write leveling module is operative for monitoring a write data stream that includes write line addresses. A property of the write data stream is detected and a write leveling process is adapted in response to the detected property. The write leveling process is applied to the write data stream to generate physical addresses from the write line addresses.

1. A memory system comprising:
 a memory including one or more limited lifetime memory devices; and
 an adaptive write leveling module connected to the memory, the adaptive write leveling module operative for:
 monitoring a write data stream for the memory, the write data stream comprising write line addresses; 
 detecting a property of the write data stream; 
 adapting a write leveling process in response to the detected property; and 
 applying the write leveling process to the write data stream to generate physical addresses in the memory from the write line addresses. 
 
 
 
     
     
       2. The system of  claim 1 , wherein the property is a number of write line addresses specifying the same write line address within a programmable time window. 
     
     
       3. The system of  claim 2 , wherein the write leveling process performs remapping between the write line addresses and the physical addresses at a programmable rate, and the programmable rate increases when the number of write line addresses specifying the same write line address increases and the programmable rate decreases when the number of write line addresses specifying the same write line address decreases. 
     
     
       4. The system of  claim 1 , wherein the monitoring is performed for a random subset of the write data stream. 
     
     
       5. The system of  claim 1 , wherein the adapting is performed during normal system operation. 
     
     
       6. The system of  claim 1 , wherein the write leveling process performs remapping at a programmable rate and the adapting comprises setting the programmable rate. 
     
     
       7. The system of  claim 1 , wherein the adaptive wear leveling module is further operative for transmitting an alert in response to the detected property reaching a programmable threshold. 
     
     
       8. A computer program product for performing adaptive write leveling in a memory system, comprising a tangible storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method comprising:
 monitoring a write data stream comprising write line addresses; 
 detecting a property of the write data stream; 
 adapting a write leveling process in response to the detected property; and 
 applying the write leveling process to the write data stream to generate physical addresses from the write line addresses. 
 
     
     
       9. The computer program product of  claim 8 , wherein the property is an estimated number of write line addresses specifying the same write line address. 
     
     
       10. The computer program product of  claim 9 , wherein the write leveling process performs remapping between the write line addresses and the physical addresses at a programmable rate, and the programmable rate increases when the number of write line addresses specifying the same write line address increases and the programmable rate decreases when the number of write line addresses specifying the same write line address decreases. 
     
     
       11. The computer program product of  claim 8 , wherein the property is a number of write line addresses specifying the same write line address within a programmable time window. 
     
     
       12. The computer program product of  claim 8 , wherein the monitoring is performed for a subset of the write data stream. 
     
     
       13. The computer program product of  claim 8 , wherein the subset is randomly selected. 
     
     
       14. The computer program product of  claim 8 , wherein the adapting is performed during normal system operation. 
     
     
       15. A memory system comprising:
 a memory including one or more limited lifetime memory devices; and
 an adaptive write leveling module connected to the memory, the adaptive write leveling module operative for:
 monitoring a write data stream for the memory, the write data stream comprising write line addresses; 
 detecting a property of the write data stream; 
 adapting a write leveling process in response to the detected property; and 
 performing the write leveling process on the write data stream to generate physical addresses in the memory from the write line addresses by applying a function to the write line addresses. 
 
 
 
     
     
       16. The system of  claim 15 , wherein the property is an actual or estimated number of write line addresses specifying the same write line address within a programmable time window.